Sulfinyl compounds, which act as proton pump inhibitors, are used in the treatment of pathologies related to an increase in gastric secretion. Examples of these compounds, known as “prazoles”, are omeprazole, esomeprazole, pantoprazole, rabeprazole, lansoprazole, tenatoprazole and hydroxymeprazole.
The synthesis of these products is substantially carried out following the scheme reported herein, in which R1-R7 and Q have, for example, the meanings defined in the disclosure.

It is evident that the process for their preparation requires many complex steps. Furthermore, a key step of the known processes is the oxidation of a thioether (—S—) intermediate to give the corresponding sulfinyl (—SO—) derivative. Hydrogen peroxide and sodium hypochlorite are usually preferred as oxidizing agents. The handling of large amounts of hydrogen peroxide involves, however, remarkable risks in term of safety of operators. Moreover, the oxidation of the thioether (—S—) intermediate, due to concomitant over-oxidation processes, can give undesired sulfone (—SO2—) derivatives which have to be removed. This involves reduced yields and longer work up times. There is therefore the need for an alternative, advantageous process for the preparation of said compounds.